1. Field of the Invention
The invention relates to a mixing valve assembly, particularly the type having a single control assembly, including thermostatic control means. The valve assembly is provided with at least one cold water inlet and at least one hot water inlet and one mixed water outlet, valve control elements for shutting off water flow, and volume control being positioned upstream relative to the thermostatic control means. One control element is in the form of a stationary valve seat and has inlet ports for cold and hot water, the ports being connected to the cold and hot water inlets at one side and directed towards a movable disc at the other side. The movable disc is displaceable on the valve seat disc and contains passages communicating with the inlet ports of the valve seat.
2. Description of Prior Art
Assemblies of this type are known, e.g. from DT-OS 28 04 755. In this known assembly which, for example, forms the starting point for the invention, the adjusting mechanism for shutting off and volume control interacts with two closing elements, which are two superimposed control discs rotatable relative to one another and arranged in front at the inlet side of the mixer valve assembly, substantially coaxially with the main axis thereof, the adjusting mechanism including a sleeve which is coaxial with the main axis, rotatable about it and rotatably connected at one end to one of the control discs. In this mixing valve assembly, shut-off and volume control are effected by means of two ceramic control discs. Control elements of this type are widely used in mixing valve assemblies, particularly so-called single-lever assemblies.
Mixing valve assemblies with a thermostatic control offer the advantage that the temperature of the mixed water is controlled automatically in accordance with a preset value, independently of the flow pressures and flow temperatures.
The thermostat control in the known mixing valve assembly which, for example, the invention takes as its starting point, is of conventional construction. The internal water chambers of the thermostatic control are in the form of annular chambers extending between the casing of the assembly and control elements in sleeve and piston form provided therein, the control elements including the thermostatic element being coaxial with the main axis of the assembly and being arranged so that some are stationary, some rotatable and some movable longitudinally, with a plurality of O-rings, particularly dynamically loaded ones, interposed. In this known assembly, shut-off and volume control are functionally separated from the thermostatic control in the normal way. Two actuating members are provided for using the assembly, again in the usual way, one to preset the temperature of the mixed water and the other for shutting off and volume control.
Mixing valve assembles of this type are complex and expensive in construction and to manufacture. Their operating reliability over long periods leaves much to be desired. The overall dimensions of the known assembly are considerable. In addition, their complex and expensive technology makes then ill suited in practice for construction in the form of a single-piece thermostat with one handle. Assemblies with one handle are becoming increasingly popular, particularly those fitted with an actuating member in the form of a lever, such as disclosed in DT-AS No. 15 50 060. A single-lever, one piece thermostat using conventional technology for thermostatic control and for shut-off and volume control is disclosed in DT-OS No. 24 13 392.